Twisted Nematic (TN) type or Super Twisted Nematic (STN) type liquid crystal displays (LCDs) are the types of displays used in watches and other common low cost monochromatic displays like energy meters. These displays are described as root mean square (RMS) responsive meaning the behavior is a function of the RMS voltage applied. The fundamental affect on the light is to rotate polarized light as it passes through the liquid crystal fluid. The amount of twist is controlled by the RMS voltage applied For twisted nematic LCDs the driver a.c. segment waveforms are constructed by predetermined timed combinations of voltage levels of e.g. half bias GND: ½:1 or one third bias GND: ⅓:⅔:1. Typically LCD drivers have been essentially multiplexers that switch an output pin connected to an LCD display between several analog voltage levels. These voltages are typically constrained to be at or below the power supply voltage of the device. The contrast on these LCDs panels depends on the RMS voltage of the waveforms applied to the pins. A 5V supply seems to be a lower level that the LCD manufacturers can design displays for with reasonable display layout complexity and cost. For CMOS processes with feature size less than 0.25 μm, 5V tolerant devices are not available for normal digital processes, and one would have to avail of the expensive 5V tolerant option to drive these panels. For the normal digital process the supply voltage is typically less than 3.6V and hence the amplitude of the output waveforms are limited by this voltage. This would imply that for certain LCD panels the RMS voltages seen by the panel might not be large enough for good contrast across the temperature range dictated by the application (−40 C −85 C). Since the required RMS voltage, for reasonable contrast, increases with decreasing temperature, even for 3-3.6V LCD panels the RMS voltage might not be enough for proper contrast at cold temperatures, if driven from a 3.6V supply.